Growth hormone secretion timing in depression: clinical outcome comparisons

Growth hormone (GH) secretion in the 100 minutes preceding sleep onset (preSO), as well as in the first half of the night (1st HN), was examined for a group of 13 healthy women and 43 women with recurrent depression who participated in a 3-year maintenance therapy study. GH studies were obtained at several points during treatment and every 3 months during maintenance, during which patients were randomly assigned to active drug or drug-free maintenance treatment cells for 3 years, or until recurrence of depression. Depressed patients were divided into subgroups according to their maintenance treatment assignment (active drug or drug free) and treatment outcome (completing in remission or having a recurrence). Imipramine caused an increase in the GH ratio in all subgroups. Protocol completers had a significantly larger imipramine-induced increase in the GH ratio than did recurrers. The difference in time of GH secretion relative to sleep onset was found to correlate with treatment outcome and was independent of medication status during maintenance.